Dispensing machine for the metered delivery and continuous homogenization of finished paint products

ABSTRACT

A dispensing machine for the metered delivery of fluid products, especially painting products. The dispensing machine includes a dispensing head with a nozzle, and the ends of a plurality of delivery ducts communicate with the dispensing head in order to feed a plurality of fluid products thereinto. A mixing device, in particular a rotating turbine, is mounted between the ends of the delivery ducts and the dispensing nozzle to continuously mix the fluid products coming from the different delivery ducts and simultaneously entering the dispensing head.

TECHNICAL FIELD

The present invention relates to a dispensing machine for the metereddelivery of fluid products, especially fluid ingredients that make upfinished products such as varnishes, paints, inks, enamels, textile dyesand similar products.

BACKGROUND ART

In order to obtain the finished products given above as examples, it isknown to add one or more colorant fluid products to a base fluid, suchas white or transparent, in predetermined proportions according tospecific formulas. Known machines used in the above industry deliverknown amounts of colorants into cans, containers, tins or bins of apredetermined capacity, into which the base fluid products havepreviously been placed. These known machines must ensure high precisionin determining the amount of colorant product to dispense, since evenslight differences in the relative proportions among the variouscolorant products or between these and the base fluid product may leadto finished products having a color that does not match the desiredresult. At any rate, after delivery by traditional dispensing machines,the distribution of colorant products in the mass of base fluid productis not homogeneous, and it is therefore necessary to shake the can moreor less vigorously.

This necessary shaking phase is obviously a burden on the productionprocess for finished products using the so-called tinting systems as itleads to additional manual labor—often difficult due to the size andweight of the cans—or the use of specialized mixing machines, therebyincreasing system costs. In any case, however, mixing also considerablyincreases the production time of finished products.

Thus, at the state of the art today, the homogenization stage is on thebottleneck in terms of the productivity of a rapid dispensing machine,and in any case limits the use of tinting systems to products with goodfluidity, and does not allow the use of highly viscous products of thosecontaining large amounts of solid or plastic particles.

SUMMARY OF THE INVENTION

The purpose of the present invention is to resolve the abovedifficulties, in particular to provide a dispensing machine of the typeindicated in the preamble of the present description that allows metereddelivery and continuous homogenization of finished painting products.The primary object of the invention is to obtain a finished, coloredpainting product at the machine outlet that does not require any furtherblending.

Another purpose of the present invention is to eliminate the mixingmachines traditionally combined with dispensing machines to increase theproductivity of a tinting system.

A further purpose of the invention is to integrate and automate thevarious production phases of finished paint products, expanding therange of component products that may be used in a tinting system.

A further purpose of the invention is to integrate and automate thevarious production phases of finished paint products, expanding therange of component products that may be used in a tinting system.

In order to achieve the above objects, the invention regards adispensing machine of the type indicate in the preamble to thisdescription, with the features set forth in the attached claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Additional features and advantages shall become apparent from thefollowing description of one preferred embodiment, with reference to theenclosed figures, provided solely as non-limiting examples, wherein:

FIG. 1 is a schematic plan view of a dispensing machine built accordingto the invention, from which the upper covering panels have been removedfor clarity,

FIG. 2 is a plan view of the dispensing unit of the machine in FIG. 1,

FIG. 3 is a longitudinal cross-section of the dispensing unit accordingto line III—III in FIG. 2,

FIG. 4 is an enlarged plan view of the dispensing head in FIG. 2,

FIG. 5 is a longitudinal cross-section of the dispensing head accordingto line V—V in FIG. 4, and

FIG. 6 is a diagram of the washing system of the dispensing head inFIGS. 4 and 5.

DETAILED DESCRIPTION

With reference now to the figures, reference number 1 indicatesgenerally a dispensing machine comprising multiple motor pump units 2,preferably housed in modular frames 3, to allow the machine to be easilyexpanded according to the number and variety of component products to bedispensed. Each motor pump unit includes a motor 4, preferably but notlimitatively a brushless electric motor, whose operation is controlledindependently from that of the motors of the other motor pump units bymeans of a control circuit of known type, preferably interfaced with acomputer. In particular, the control circuits regulate the rotationspeed of the motors 4, each of which is connected to the shaft of acorresponding positive-displacement pump 5 provided with inlet openings6 and outlet openings 7. The inlet openings 6 are connected toreservoirs (not shown in the figure) of component products-bases,colorants, various types of additives, etc. The outlet openings areinstead connected to distribution lines 10 (the path of which is shownby the dashed line in FIGS. 2 and 3), with the interposition ofthree-way, two-position recirculation valves 11 a, 11 b, from which therecirculation lines also branch out to return the component products totheir respective reservoirs. The distribution lines 10 are conveyed to adispensing unit 8, located in the upper portion of a central dispensingmodule 9, which also preferably contains the control electronics of themotor pump units 2 and the recirculation valves 11 a, 11 b associatedwith each reservoirs, as well as the computer.

As can be seen more clearly in FIGS. 2 and 3, the ends of thedistribution lines 10 are closed by valve devices 12, preferably pinvalves, which may open selectively to connect the distribution lines 10to an axial bore 13 a of a dispensing head 13, which opens to theoutside through a dispensing nozzle 13 b. A mixing device, for example aturbine 20, rotating around a substantially vertical axis Z—Z, ismounted inside the dispensing head 13. In particular, although notlimitatively, the turbine 20 is attached to one end of a rotating shaft14, a wheel or pulley 15 being keyed to the other end thereof whichextends above the dispensing unit 8. The pulley 15 is connected to apulley or drive wheel 17, attached to the shaft of a mixing motor 18, bymeans of a belt or chain 16. It is obviously possible to adopt differentbut functionally similar construction systems to transmit motion fromthe motor 18 to the mixing device 20, such as for example a geartransmission, a universal joint, or other functionally similar system.

FIGS. 2 and 3 show a sample configuration of the dispensing unit 8 of adispensing machine adapted to dispense up to sixteen different bases andsixteen different colorants. The three-way valves 11 a, which provideselective dispensing of bases or their recirculation to thecorresponding reservoirs, are arranged in a semicircle around thedispensing head 13.

The three-way valves 11 b, smaller because they are used to selectivelydispense colorants, are arranged in arcs on both sides of the motor 18.The pin valves 12, one for each three-way valve 11 a, 11 b, are arrangedin a circle around the dispensing head 13. To keep the system compact,in the configuration shown the pin valves 12 are stacked vertically inpairs, as can be clearly seen in FIGS. 3 and 5.

As can be more clearly seen in FIGS. 4 and 5, the pin valves 12 aremounted on a ring support 40, wherein radial ducts 41 are provided inwhich the pins 42 of the valves 12 can move axially, selectivelycontrolled by actuators 43. Each radial duct 42 communicates with acorresponding inlet opening 44, to which a corresponding line 10 isconnected as it arrives from the three-way valves 11 a, 11 b. The radialducts 41 open into one or more shared chambers 45 which, in turn,communicates with the axial bore 13 a of the dispensing head 13,upstream from the turbine 20.

Between dispensing a finished product having a certain formula and thenext product, having a different formula, it is necessary to clean theshared nozzle 13 and the turbine 20. To this end, the machine 1comprises a washing unit 21 illustrated schematically in FIG. 6.

The washing unit 21 comprises a pressure regulator 22, through whichcompressed air from a pneumatic infeed circuit 25 is delivered. Thecompressed air is sent through a non-return valve 23 to a tank 24containing a solvent suited to the type of colorant products and basesused. The solvent is added to the tank 24 through a cap 26, afterdeactivating or closing the pneumatic infeed circuit 25. A safety valve27 ensures that the pressure in the tank does not exceed a desiredpreset level. An outlet duct 28 connects the tank 24 to a manifold 30,from which in turn leads a washing duct 29 that opens into thedispensing head 13, upstream from the turbine 20. Along the outlet duct28 there are interposed a filter 31 and a solvent washing solenoid valve32 that selectively enables entry of the solvent into the dispensingnozzle 13.

The compressed air coming from the pneumatic infeed circuit 25 is alsoused to feed the solenoid valves 11 a, 11 b through the ducts 47, afterpassing through a second pressure regulator 33. The air outlet duct fromthe second regulator 33 also communicates with the manifold 30, with theinterposition of an air washing solenoid valve 34. A discharge duct 35is also connected to the manifold 30, and is selectively closed by adischarge solenoid valve 36.

During operation of the dispensing machine 1, a predetermined formuladefining the proportions of components products to make up a certainfinished product is, for example, selected or entered by the user viathe computer. A consent command enables transmission of data from thecomputer to the control systems of the motor pump units 2, whichregulate the speed of the motors 4 and thus the flow rate of the pumps5. Until the speed and throughput of all of the pumps 5 involved in theformula has stabilized, the solenoid valves 11 a, 11 b are kept in therecirculation position. When a steady condition is reached, therecirculation valves 11 a, 11 b and the pin valves 12 for the productsrequired by the formula, generally comprising a base and one or morecolorants, are opened simultaneously to convey said ingredients to thedispensing unit 8. The component products enter the chambers 45, thenmove into the dispensing head 13 in predetermined proportions in termsof amount per unit of time. The products are then immediately blended bythe mixing turbine 20 powered by the motor 18, which may be run atconstant or variable speed depending on the component products, so as toprovide the turbine 20 with a preferably high speed, sufficient to blendthe component products perfectly. Thus the finished product arrives atthe outlet of the dispensing nozzle 13 b, and only needs to be packagedin the desired containers.

The automatic washing unit 21 of the dispensing head 13 is activatedupon a command sent by the computer at each formula change. The washingcycle takes place with the solenoid valves 11 a, 11 b in recirculationposition, with all pin valves 12 closed, with the discharge solenoidvalve 36 and air washing solenoid valve 34 closed, and with the turbine20 activated. The solvent washing solenoid valve 32 opens to allowsolvent to enter the dispensing head 13, upstream from the turbine 20.The solvent delivery phase lasts long enough to allow complete andthorough washing of the chambers 45, the dispensing head 13 and themixing turbine 20. When this phase is complete by closing the solventwashing solenoid valve 32, a new phase begins in which air enters thanksto the opening of the air washing solenoid valve 34. This phase removesany residual solvent remaining inside the dispensing head 13 and incontact with the turbine 20. The washing cycle is completed by switchingthe air solenoid valve 34 to the closed position and by opening thedischarge solenoid valve 36. This discharge valve 36 is also kept openwhile fluid products are dispensed, to avoid surge pressures in thedispensing nozzle. To better understand the operating principle of thedispensing machine described above in one particular embodiment, aspecific example of dispensing with details regarding machine parts,which must not be construed as restrictive in any way, is hereinbelowdescribed.

EXAMPLE 1

Pumps 5 have been selected having different specifications fordispensing bases and colorants.

For colorants, the pumps have a flow rate of 3 ml of product perrevolution, and can achieve a maximum rotation speed of 150 rpm. For thebases, the pumps have a flow rate of 25 ml per revolution, and a maximumspeed of 150 rpm.

Let us assume we wish to produce a finished paint product having asimple formula, in which a base B is diluted by 1% of its volume with acolorant C. The finished product, having a known specific weight, shouldhave a total weight corresponding to a volume of 1010 CC.

To produce the desired amount of product in the shortest possible time,the base pump B is set up to rotate at its maximum speed of 150 rpm,corresponding to a flow rate of 62.5 ml/s of base product. The timeneeded to dose 1000 cc of base product is therefore 16 seconds. Thecentral computer thus calculates the flow rate of colorant C needed todispense 10 cc in 16 seconds, so that the proportion between the baseand colorant entering the dispensing nozzle is constant over time. Giventhe displacement of the colorant pump, the computer system calculatesthat the corresponding motor must run at a speed of 12.5 rpm. Thisinformation is sent to the control system of the motor 4, which bringsthe circulation flow in the recirculation circuit to the required cyclespeed.

The two products involved in the formula, base B and colorant C, arethus sent to the dispensing head 13 and mixing device 20 at the aboverates.

Within 16 seconds, the dispensing nozzle 13 b releases the requiredamount of finished product, already dosed and blended.

The machine according to this invention may be built with fluid productreservoirs mounted directly on the machine, or located in adjacentmodules, or may have only the central structure 9 containing thedistribution unit and a set of inlet openings to which one may connectfluid feed lines from external or remote reservoirs via generally knowmeans, such as through a screw coupling or quick fitting.

Naturally, the principle of the invention remaining the same, theembodiments and development details may vary widely from those describedand illustrated without exceeding the extent of the present invention.

What is claimed is:
 1. Dispensing machine for the metered delivery offluid products, especially painting products, comprising a dispensinghead with a dispensing nozzle, a plurality of delivery ducts having endswhich communicate with the dispensing head to feed fluid productsthereinto, mixing means disposed between the ends of the delivery ductsand the dispensing nozzle to continuously mix the fluid products comingfrom different delivery ducts and simultaneously entering the dispensinghead, wherein the mixing means includes a rotating turbine, the deliveryducts being radial ducts the ends of which communicate with one or moreshared chambers placed upstream from the mixing means in relation to thedispensing nozzle.
 2. Dispensing machine according to claim 1, furtherincluding a plurality of reservoirs for the fluid products to bedispensed, pumping means being interposed on the ducts to transfer thefluid products from the reservoirs to the dispensing head.
 3. Dispensingmachine according to claim 2, wherein the pumping means are adjustableto transfer different fluid products at different flow rates. 4.Dispensing machine according to claim 1, further including a pluralityof reservoirs for dispensing the fluid products and interception meansinterposed on the ducts to selectively interrupt the transfer of fluidproducts from the reservoirs to the dispensing head.
 5. Dispensingmachine according to claim 4, wherein the interception means includeopenable and closable valves disposed at the ends of the ducts whichwhen open communicate with the dispensing head.
 6. Dispensing machineaccording to claim 4, wherein the interception means include three-wayvalves from which recirculation ducts branch off to selectively transferthe fluid products either to the dispensing head or to the reservoirs.7. Dispensing machine according to claim 5 wherein an even number of thevalves are arranged circularly and are stacked vertically in pairsaround the dispensing head.
 8. Dispensing machine according to claim 1,further including a washing unit having a solvent tank to which a firstsolvent washing duct is connected, a second air washing duct connectedto a source of compressed air, the first and second washing ductscommunicating with the dispensing head with the interposition ofrespective interception means which are selectively activable to open orclose the communication between the washing ducts and the dispensinghead.
 9. A machine for dispensing a fluid product such as paint, saidmachine comprising: a dispensing head defining a nozzle therein throughwhich the fluid product is discharged; a plurality of fluid deliveryducts for feeding fluid products into said dispensing head from aplurality of fluid reservoirs; and a mixing arrangement including abladed turbine disposed within said dispensing head, said turbinedefining a rotational axis about which said turbine rotates to mix fluidproducts simultaneously entering said dispensing head from therespective fluid delivery ducts, wherein terminal ends of said fluiddelivery ducts communicate with a shared chamber which is coaxiallyoriented with said turbine axis and located on an upstream side of saidturbine, said nozzle being coaxially oriented with said turbine axis ona downstream side of said turbine.
 10. The device of claim 9 whereinsaid dispensing head defines a bore in which said turbine is disposed,and said mixing arrangement includes a rotating shaft disposed withinsaid bore to which said turbine is connected for rotation therewith. 11.The device of claim 10 wherein said chamber is defined around saidshaft.
 12. The device of claim 10 wherein said dispensing head and saidshaft are vertically oriented, a lower end of said shaft being connectedto said turbine and an upper end of said shaft being operativelyconnected to a motor for driving said shaft.
 13. The device of claim 9further including a first plurality of valves each of which is providedat said terminal end of a said fluid delivery duct to control flow offluid into said shared chamber, and a second plurality of valves each ofwhich communicates with a said fluid delivery duct upstream of therespective first valve to selectively allow flow of the respective fluidproduct to said dispensing head through said fluid delivery duct or tothe respective reservoir through a recirculation duct.
 14. The device ofclaim 13 wherein said first plurality of valves are pin valves which aremounted in a generally circular arrangement on a ring-shaped supportwherein pairs of said pin valves are mounted in a vertically stackedmanner on said support, and said second plurality of valves arethree-way, two position valves which are arranged in a generallycircular arrangement in surrounding relation with said pin valve.